CF816B Karen and Coffee

思路：

有点类似于区间修改点查询的树状数组。

实现：

 #include <iostream>
 #include <cstdio>
 using namespace std;

 const int MAXN = ;
 int a[MAXN], n, k, q;

 int main()
 {
         cin >> n >> k >> q;
         for (int i = ; i < n; i++)
         {
                 int l, r;
                 scanf("%d %d", &l, &r);
                 a[l]++; a[r + ]--;
         }
         for (int i = ; i < MAXN; i++) a[i] += a[i - ];
         for (int i = ; i < MAXN; i++)
                 if (a[i] >= k) a[i] = ;
                 else a[i] = ;
         for (int i = ; i < MAXN; i++) a[i] += a[i - ];
         for (int i = ; i < q; i++)
         {
                 int l, r;
                 scanf("%d %d", &l, &r);
                 printf("%d\n", a[r] - a[l - ]);
         }
         return ;
 }